Primary Proteins:
  1. rsFastLime
    Secondary Proteins:
  1. Dronpa-2
Add photostability measurements


In the fluorescent equilibrium state, we find that the chromophore adopts exclusively the cis isomeric form. Surprisingly, the chromophore environment of Dronpa is almost identical to that of KikG, a fluorescent protein that does not exhibit photoswitching. Furthermore, we find structural similarities to asFP595 that point to a cis–trans isomerization of the chromophore as a key event in photochromic switching. Based on this assumption and the obtained structural information we generated rsFastLime (Dronpa-V157G) and Dronpa-M159T [aka Dronpa-2], two variants that exhibit strongly accelerated switching kinetics. Our findings support the view of a photoinduced cis–trans isomerization of the chromophore in Dronpa.